SSL Lookup

Free SSL Lookup Tool

The SSL Lookup tool checks any domain’s SSL/TLS certificate and server configuration in seconds. It reveals issuer, expiration, SANs, chain health, and supported protocols so you can prevent downtime and security warnings. Use SSL Lookup when launching, renewing, or troubleshooting HTTPS for websites, APIs, and SaaS endpoints.

What is SSL Lookup?

SSL Lookup is a diagnostic tool that inspects a server’s SSL/TLS certificate and HTTPS configuration. By entering a domain, it fetches and analyzes the certificate chain, validity dates, Subject Alternative Names (SANs), signature algorithms, and supported TLS versions and cipher suites. It helps verify correct installation and detect misconfigurations before they cause browser errors or outages.

Use the SSL Lookup tool on Monkey Type to quickly confirm whether your certificate is valid, trusted by browsers, and served with the right intermediates. It also checks for hostname mismatches, weak protocol support, and common issues that trigger “Not Secure” warnings, failed handshakes, or mixed content problems.

If you’re setting up a new domain, pair SSL Lookup with DNS Lookup to confirm A/AAAA/CNAME records resolve correctly before testing HTTPS. You can also combine it with WHOIS Lookup to verify domain ownership details during audits.

Why Use SSL Lookup?

• Prevent expirations and downtime: Instantly see certificate expiration dates and renewal windows so you can renew before users see browser warnings.
• Verify correct installation: Confirm the full chain (server, intermediate, root) is presented and the Common Name or SAN matches the domain, including www and subdomains.
• Troubleshoot handshake errors: Identify protocol or cipher mismatches (e.g., server only supports TLS 1.0) that break older clients or strict security policies.
• Strengthen security posture: Check for weak algorithms, missing HSTS, or outdated ciphers, and then harden your configuration.
• Compliance and audit readiness: Generate a quick snapshot of issuer, key type, and validity to document HTTPS compliance for audits and vendor reviews. For a complete view of your path to site, use the HTTP Headers tool to validate HSTS and cache directives.

How to Use SSL Lookup on Monkey Type

1. Enter a domain: Type the domain or subdomain (for example, example.com or api.example.com). If needed, include a custom port like example.com:8443.
2. Run the check: Click “Lookup.” The tool opens a secure connection, retrieves the certificate chain, and probes supported TLS versions.
3. Review certificate details: See issuer, subject, SANs, expiration date, serial number, fingerprints, and key information (RSA/ECDSA).
4. Validate chain health: Confirm intermediates are served correctly and the chain is trusted. The report flags incomplete chains or untrusted issuers.
5. Assess TLS configuration: Check supported TLS versions and cipher suites, forward secrecy support, and whether HSTS is detected.
6. Take action: Renew certificates nearing expiry, add missing intermediates, update ciphers, and enable modern protocols as needed.

Expected results: You’ll receive a concise pass/fail for chain trust and hostname match, precise expiration timing, SAN coverage, and clear guidance on weak protocols. For deeper network context, run an IP Lookup to see where the domain resolves and confirm geo or ASN details that might affect CDN edges.

Key Features

• Full certificate breakdown: Subject, issuer, validity period, SANs, serial, and SHA-256 fingerprint.
• Chain validation: Detects missing or incorrect intermediates that cause trust errors.
• Hostname verification: Ensures the certificate covers the exact domain and subdomains.
• TLS version and cipher scan: Highlights support for TLS 1.2/1.3 and flags deprecated protocols.
• HSTS detection: Checks if Strict-Transport-Security is present via response headers; use alongside HTTP Headers for full header insights.
• SNI support: Handles multi-tenant servers by specifying the Server Name Indication during the handshake.
• Wildcard and SAN coverage: Confirms whether all intended hostnames are protected.

Best Practices & Tips

• Monitor expiry proactively: Check certificates regularly and renew 30 days before expiration to avoid outages.
• Test all hostnames: Run SSL Lookup for root (example.com), www (www.example.com), and key subdomains (api, cdn). Confirm SAN coverage or use a wildcard where appropriate.
• Include intermediates on the server: Most trust failures come from missing intermediate certificates. Install the full chain provided by your CA.
• Harden protocols and ciphers: Disable SSLv3/TLS 1.0/1.1, prefer TLS 1.2/1.3, and select modern cipher suites with forward secrecy.
• Validate redirects and headers: After enabling HTTPS, confirm 301 redirects from HTTP to HTTPS and correct security headers using the HTTP Headers tool.
• Check DNS and WHOIS during moves: When migrating or changing CAs, verify records with DNS Lookup and ownership with WHOIS Lookup to reduce misconfigurations.

Common Use Cases

• Pre-launch validation: Before going live, ensure the certificate is valid, trusted, and covers all hostnames used by your app and CDN.
• Renewal verification: After renewing or switching to a new CA, confirm the new chain is installed and no legacy cert is still served.
• Troubleshooting browser warnings: Resolve “Your connection is not private” errors by checking chain trust, hostname match, and expiry.
• Protocol mismatch fixes: Diagnose client handshake failures caused by outdated TLS/ciphers on servers or proxies.
• Audit and compliance checks: Capture issuer, key type, and validity data for security reviews. For additional context on infrastructure, pair with IP Lookup.

Frequently Asked Questions

Is there a difference between SSL and TLS?

Yes. SSL is the older protocol, and TLS is its modern successor. People still say “SSL certificate,” but browsers use TLS. The SSL Lookup tool reflects current TLS versions and ciphers while maintaining the familiar terminology.

How often should I run an SSL Lookup?

Run it after every certificate issuance or renewal, and schedule periodic checks—monthly or after configuration changes. Always test both the apex domain and key subdomains. For DNS-related changes, also run a quick DNS Lookup.

What is a SAN and why does it matter?

SAN (Subject Alternative Name) lists all hostnames secured by a certificate. If your domain isn’t in the SAN list, browsers will show a mismatch error. Use SSL Lookup to ensure every required hostname is covered.

Why does the tool say my chain is incomplete?

Your server may be missing one or more intermediate certificates. Install the full chain from your certificate authority. After updating, rerun SSL Lookup to confirm trust and chain order are correct.

Can I check non-standard HTTPS ports?

Yes. Append the port to the domain (for example, example.com:8443) and run SSL Lookup. This is useful for admin panels, staging environments, or services that don’t use the default 443 port. Use Monkey Type for quick, repeatable checks across environments.